Mayak

The Mayak Production Association (Russian: Производственное объединение «Маяк», from Маяк "lighthouse") is an industrial complex which is one of the biggest nuclear facilities in the Russian Federation. It housed plutonium production reactors and a reprocessing plant. Located 150 km south-east of Ekaterinburg between the towns of Kasli and Tatysh 72 km northwest of Chelyabinsk, the closest city to the nuclear complex is Ozyorsk, the central administrative territorial district. As part of the Russian nuclear weapon program, Mayak was formerly known as Chelyabinsk-40 and later as Chelyabinsk-65 after the postal codes of the site.